In order i would try

Pretreat with Lestoil (if spouse is a car hobbyist you should have this on hand lol) then wash hot, don't tumble dry

Pretreat with dishsoap like Dawn then wash hot, same deal

Or dry laundry chalk like Janie, but I think this sounds like it would be too much for her!

I have a little laundry brush that is helpful for lathering this stuff into the stains.

If the suggestions given already don't work, try CitraSolve or similar (a citrus turpene) . Rinse the spot well with warm to hot water, before putting into the washing machine to launder.

Mechanics hand soap.

Mechanics at work recommended citra solve.

Thank you so much for all the suggestions. Before I read your helpful answers, I tried wetting the stain and rubbing an Astonish bar on the stain, then adding the shirt to a regular, hot temperature, wash. It worked! I've had two of these bars for "centuries," and haven't used the product much. I just did a web check, and the stuff is still sold.

I really appreciate your interest and help.

I'd never heard of it! thanks for the update.